Purifying of alkylolamides



Patented Dec. 3, 1946 PURIFYING OF ALKYLOLAMIDES Harland H. Young, Chicago, 111., and David Rubinstein, Brooklinc, Mass., assignors to Industrial Patents Corporation, Chicago, 111., a

corporation of Delaware No Drawing. Application April 14, 1943,

Serial No. 483,062

4 Claims.

1 I V This invention relates tothe purifying of alkylolamides and more particularly to the removal of basic substances from mixtures containing alkylolamides including mixtures resulting from reacting fatty or other organic acids oresters duce alkylolamides.

alkylolamides of the acids.

themselves with alkylolamines.

esters.

as the alcohol of the ester.

of free nitrogen functions.

olamide monoacid ester.

2 soluble precipitates or foots separable from the mixture in any desired manner such as settling, filtration, or centrifugal separation. By treating the reaction mixture with the acidic material in the presence of a small amount of water the A precipi- This precipitate in most 5 of such acids with alkylolamines in order to proneutralization reaction is facilitated and. other Esters of fatty or other ormaterials such as the glycerol or other alcohol ganic acids with glycerol or with other m'onowhich may be present in the mixture are usually hydroxy, dihydroxy or trihydroxy alcohols will removed as part of the foots. react with alkylolamines to produce reaction It is, therefore, the object of the present in-. mixtures in which a large number of compounds vention to remove basic and other impurities exist in equilibrium. This reaction, if carried from mixtures containing alkylolamides so as on in the presence of an excess of the alkylto produce purified alkylolamides. 1: olamine and under carefully controlled condi- Another object of the inventionxis to provide tions can be made to consist predominantly of a process by which basic impurities are removed Similarly, reaction from crude alkylolamides as an insoluble precipimixtures can be produced by reacting the acids tate. 1

Thus by react- Another object of the invention is to provide ing alkylolamines with fatty acids an equilibrium a process of purifying alkylolamides containing mixture is produced containing the fatty acids, basic impurities by the employment of acidic the alkylolamine, alkylolaminesoaps, alkylolmaterials forming insoluble precipitates or foots. amine esters, alkylolamides and alkylolamide Another object of the invention is to provide a If the reaction is carried on between an process of purifying alkylolamides of fatty acids alkylolamine and esters of fatty acids, the reacin which strong mineral acids or compounds of tion mixture may also contain the ester as well 5 such acids with weak bases are employed to form Other by-products insoluble precipitates with basic reacting impuriof unknown structure may exist but such byties. I products are in general basic in reaction because A further object of the invention is to provide a process of purifying alkylolamides of fatty The present invention is directed to removing acids containing basic impurities in which the the basic impurities in such mixtures and is paralkylolamides are dissolved in an inert solvent ticularly applicable to reaction products between and the impurities are neutralized to form comglycerides of higher fatty acids such as vegetable pounds insoluble in the solvent. or animal oils and either mono-alkylolamines or A still further object of th invention i t dialkylolamines. By reacting the glyceride with provide a proce of p fy ng alkylolamides 0011- an alkylolamine in the presence of an excess of taining basic impurities in which a solidvacid the alkylolamine a reaction mixture consisting reaction ma e s p y d to remove such predominantly of alkylolamides of the higher impurities I 7 fatty acids can be produced which alkylolamides The prefe d practice of the present invention exist in equilibrium with alkylolamine, glycer- 40 includes the addition of a strong mineral acid in ides, glycerol, alkylolamine soaps and alkylola small quantity of water to the reaction prodamine esters as well as alkylolamide esters. If nets of an alkylolamine and a glycerol ester of the reaction is with a dialkylolamine there are higher fatty acids which reaction products conalso other possible reaction products such as the tain basic impurities such as the alkylolamine, dialkylolamine monoacid ester and the dialkylalkylolamine esters, alkylolamine soaps, etc.

The basic reacting Sufficient acid is preferably added and thormaterials, among Which arealkylolamine soaps, oughly admixed with the reaction products to excess alkylolamine and alkylolamine esters neutralize all of the basic impurities. cause the reaction products to develop off flavors tate forms which is insoluble in the alkyolamides and odors which deleteriously affect the mixtures or ny y er l esters or alkylolamide esters for use in edible and other products It has been which are present. found that substantially all of the materials cases readily settles and can be removed by de.-. causing such deleterious flavors, or odors, can canting the alkylolamides or by filtration orcenbe removed from the mixture by neutralization trifugal separation. This precipitate is generally flocculent and resembles, the foots.. obtained. in

with an acidic material which willproduce in-,

arating the precipitate from the alkylolamides as this precipitate is also insoluble in the lyceride oil. Any alkylolamide esters present are also retained in the glyceride oil andare not objectionable. The temperature of refining will vary with different alkylolamides depending upon the alkylolamine employed or the fatty acids present in the alkylolamide and upon the nature of the glyceride oil solvent, if one is employed. In general the temperature should be suiiiciently high to render fluid the crude reaction mixture or the glyceride oil in which it is incorporated. Thus, when refining alkylolamides or alkylolamides admixed with glyceride oils containing substantially saturated fatty acid radicals, such materials should be'heated to a temperature suificiently above the melting point to render them fluid prior to the refining operation. Thus the temperatures employed may range between approximately 70 F. and 180 F. although in some cases higher temperatures may be desirable.

The preferred reagent is phosphoric acid in a concentrationbetween approximately 50% and 90%, as such phosphoric acid also makes it possible to selectively remove the impurities. Thus, the alkylolamine phosphate is somewhat more insoluble than the alkylolamine ester phosphate and. can be selectively precipitated to remove it from either the alkylolamide alone or from the alkylolamide dissolved in a glyceride oil or other ester of a. higher fatty acid. By adding just slightly more phosphoric acid solution than that necessary to react with the alkylolamine, this material can be substantially completely removed from the mixture after which additional phosphoric acid solution can be added to precipitate the alkylolamine ester phosphate. Other strong mineral acids such as sulfuric and hydrochloric acids in substantially the same concentration referred to above can, however, be employed to remove the basic impurities from the alkylolamides.

Other acid reacting materials may also be employed to remove basic impurities. For example, various salts of strong acids such as sulfuric, hy-

drochloric, and phosphoric with weak bases in r the form of granular salts can be employed as filters through whichthe crude alkylolamide mixture is passed. The admixture of a small amount of moisture or Water with the crude alkylolamide mixture facilitates the removal ofthe basic impurities. 'It -is-also possible to suspend such acid reacting salts by agitation in the crude mixture or-crude mixture combined with a solvent, and allow the same to settle. Such operation causes the basic ingredients of the crude mixture to react with the salts andinsolu-ble products formed thereby to be removed from the mixture. The dampening of the granular salt with a small amount of water prior to admixing the same with the mixture to be refined or the addition of a small .amount of Water to the mixture during refining with the granular material assists in the reaction with'the basic materials. It is apparent that concentrated solutions or .s'lurri'es of such acid reactingsalts may also be employed as a refining agent. Many other acid reacting materials such as lower fatty acids neutralize the alkaline impurities in the reaction mixtures above referred to but yield compounds which retain their solubility in the mixture, which compounds cannot be easily removed from the mixture. The invention, therefore, is concerned with the employment of acids or acidic materials which form insoluble precipitates with the basic impurities,

mineral acids or their salts with weak bases being the preferred acidic material, but any acid reacting-material either organic or inorganic which is sufficiently acid'to neutralize the basic materials and which produces insoluble foots which may be removed from the reaction mixture may be employedin the present invention. Materials other than strong acids which are contemplated for use hydrides, acid chlorides, or other acylating agents all of which acylating agents are included in the term lypophyllic acylating agents. In general it is desired to remove all of the materials in the reaction mixture which have a, free nitrogen function which includes any alkylolamine present or the alkylolamine esters. Any alkylolamine soaps are also decomposed to liberate the amine so thatthe amine portion of such compounds may likewise be removed from the mixture. Also, glyceride oils or fats havebeen described as a solvent for the reaction material during the refining operation. It will be apparent that any inert solvent for the alkylolamides being treated may be employed. The foots produced by the refining operation may be removed from such admixtures by filtration, decantation or centrifugal separation and other impurities such as coloring matter, etc., are to a large extent removed with the foots by adsorption thereon.

While we have described the preferred embodiments of our invention, it is understood that the details thereof may be varied within the scope of the following claims.

We claim:

1. The method of purifying alkylolamides associated with other reaction products formed in reacting alkylolamines with fatty acids and their esters and containing alkylolamides, and other basic substances of bitter flavor, which comprises treating thecrude alkylolamides with an aqueous solution of a mineral acid material in a glyceride solvent for said alkylolamides and alkylolamine esters to neutralize said basic substances and to precipitate the same as insoluble compounds, while maintaining the temperature suflicien-tly highduring the treatment to render'the solution of .alkylolamides in a liquid condition and thereafter separating said compounds from the purified alkylolamides.

2. The method of purifying crude alkylolamides of higher f-at-tyacidsformed by reacting an excess products of a basic nature and having a bitter flavor, which comprises contacting a solution of 5 6 said crude alkylolamides in a glyceride oil with 3. The method according to claim 2 in which an aqueous solution of a neutralizing agent conthe neutralizing agent is aqueous phosphoric acid taming a mineral acid to convert said basic subof about 50% to 90% concentration. stances into insoluble salts, supplying suflicient i. The method according to claim 2 in which heat during the operation to keep the solution of 5 the glyceride oil is triglyceride fat. alkylolamides in a liquid condition and then separating said insoluble salts from the solution of HARLAND H. YOUNG. purified alkylolamides. DAVID RUBINSTEIN. 

